The popular VVGNG-LS cable is designed for wiring equipment in rooms, in the open air, electrical installation products (channels, tunnels, pipes, trays, etc.), provided that there are no tensile loads on the product. Equipment of this series is also used when necessary to ensure increased fire safety.
VVGNG LS from the VVGNG cable is distinguished by the fact that its design uses insulation that is not able to emit large amounts of smoke during smoldering.
In the name of the wire, the LS index means Low Smoke, which means “low smoke” (insulation and sheath are made of fireproof plastic compound that does not spread combustion).
Application
VVGNG-LS cable is designed for operation in cold, temperate or tropical climates. This type of wire can be used both on land and in lakes, rivers at an altitude of up to 4300 m.
Applicable power cable:
- in the air, provided there is no threat of mechanical damage during operation;
- in dry or damp rooms (collectors, tunnels, canals, production rooms, structures subject to partial flooding, etc.);
- in blocks, on bridges, special cable racks;
- in hazardous areas;
- in fire hazardous facilities;
- for laying lighting group networks in hazardous areas.
The weight of the VVGNG-LS cable allows it to be used for vertical, horizontal or inclined paths. A wire of this type unarmoured can be operated in places with vibration.
It is not recommended to use it for underground laying (in earthen trenches and land) without the use of special protective cable systems (for example, a metal hose or HDPE pipe), which exclude damage to the conductor sheath and preserve its operational characteristics throughout the entire life cycle.
Design Features
- Conductors are made of copper and can be single or multi-wire, have a sector or round shape. GOST provides for I or II class of flexibility.
- The core insulation is made of polyvinyl chloride plastic compound, which has increased fire protection and reduced smoke emission. Each insulated core in multicore cables is made of PVC in different colors. Traditionally, the zero wires are blue, the grounding is yellow-green in color or indicated by the number "0".
- The inner sheath of the cable is laid over insulated cores, filling the voids between them and creating an additional refractory protective layer between the outer insulation and the core.
- The outer shell is made of polyvinyl chloride composition and has increased fire resistance. If the diameter of the cable cores does not exceed 16 mm, between the core and the outer sheath it is permissible to fill the space with a special refractory composition. In this case, the inner shell is optional.
Diameter of cable VVGNG-LS
The cores of a two-wire wire have the same cross-sectional diameter. If the number of cores is 3-5, one of them may be of smaller diameter. This is a ground wire or ground wire.
The diameter and weight of the VVGNG-LS cable are calculated depending on the number of conductive cores in the structure, its design features, etc.
Key Specifications
VVGNG-LS cable is used when laying and installing electrical networks from power distribution boards or transformer substations to energy consumption facilities: production workshops, residential and administrative buildings, construction projects, household and utility enterprises, etc. It is allowed to lay the supply wire in concrete trays , tunnels, on supporting racks.
The wire it is designed for electric power transmission, the power of which for alternating current is 0.66 kV or for direct current - 1 kV.
The outer shell is made of materials that are not exposed to ultraviolet radiation, therefore it is allowed to lay the product in the open sun. VVGNG-LS cable not recommended for laying in unprotected earthen trenches.
- Permissible air temperature at which prolonged use of the cable can be carried out is -50 ... + 50 °
- Humidity is allowed up to 98% (at a temperature of +35 ° C)
- Cable laying is allowed to be carried out at a temperature not lower than -15 °
- Operating t heating cores - +70 °
- Maximum t in emergency mode - +90 ° (operation no more than 8 hours a day and no more than 1000 hours throughout the entire service period)
- Non-ignition of insulation at t +400 °
- Cable length, core diameter of 1.5-16 mm, is 450 m; for cable with conductors with a diameter of 25-70 mm - 300 m; if the core diameter is 95 mm or more - 200 m.
- The warranty operational period from the date of commissioning is 5 years, from the date of manufacture - not more than 6 months.
- The service life is up to 30 years
Quality control
The following control methods allow you to make a preliminary conclusion about the quality of the cable if the obtained values from the regulated significantly differ. However, the final conclusion on the conformity of this GOST material can only be made after testing it in a specialized laboratory according to strict methods and in the volumes indicated in the standard.
Visual inspection and measurement
Visually, you can check the number and color of the wires, the number of wires in the core, the integrity of the sheath and insulation, the ease of separation.
Using measuring tools, you can check the thickness of the shell and insulation. The measurement of the diameter of the wire and the calculation of the cross-section of the cores according to a special formula does not apply to the strict control method, since the cross-section confirms the electrical resistance. Nevertheless, a significant deviation (by more than 10%) of the calculated cross section from the nominal one may become the basis for doubts about the quality.
Winding test after keeping at low temperature
In this way, when having a large freezer with a temperature of up to -15 ° , the quality of the cable sheath, the outer diameter of which is up to 20 mm, is checked. To do this, a cable segment (length of approximately 1.2 m), rolled up for compactness into a ring, is placed for 45 minutes in the freezer, then it is removed and winding onto the drum for 5 minutes is carried out in a full turn. The diameter of the drum should be 15 ∙ (Dn + d) ± 5%, where Dn is the outer diameter of the VVGng-LS cable in mm, d is the core diameter in mm. At the same time, a high-quality shell should not have cracks and tears.